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<FONT color="green">001</FONT>    /*<a name="line.1"></a>
<FONT color="green">002</FONT>     * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<FONT color="green">003</FONT>     * contributor license agreements.  See the NOTICE file distributed with<a name="line.3"></a>
<FONT color="green">004</FONT>     * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<FONT color="green">005</FONT>     * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a>
<FONT color="green">006</FONT>     * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<FONT color="green">007</FONT>     * the License.  You may obtain a copy of the License at<a name="line.7"></a>
<FONT color="green">008</FONT>     *<a name="line.8"></a>
<FONT color="green">009</FONT>     *      http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<FONT color="green">010</FONT>     *<a name="line.10"></a>
<FONT color="green">011</FONT>     * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<FONT color="green">012</FONT>     * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<FONT color="green">013</FONT>     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<FONT color="green">014</FONT>     * See the License for the specific language governing permissions and<a name="line.14"></a>
<FONT color="green">015</FONT>     * limitations under the License.<a name="line.15"></a>
<FONT color="green">016</FONT>     */<a name="line.16"></a>
<FONT color="green">017</FONT>    package org.apache.commons.math3.random;<a name="line.17"></a>
<FONT color="green">018</FONT>    <a name="line.18"></a>
<FONT color="green">019</FONT>    import java.io.Serializable;<a name="line.19"></a>
<FONT color="green">020</FONT>    <a name="line.20"></a>
<FONT color="green">021</FONT>    <a name="line.21"></a>
<FONT color="green">022</FONT>    /** This abstract class implements the WELL class of pseudo-random number generator<a name="line.22"></a>
<FONT color="green">023</FONT>     * from Fran&amp;ccedil;ois Panneton, Pierre L'Ecuyer and Makoto Matsumoto.<a name="line.23"></a>
<FONT color="green">024</FONT>    <a name="line.24"></a>
<FONT color="green">025</FONT>     * &lt;p&gt;This generator is described in a paper by Fran&amp;ccedil;ois Panneton,<a name="line.25"></a>
<FONT color="green">026</FONT>     * Pierre L'Ecuyer and Makoto Matsumoto &lt;a<a name="line.26"></a>
<FONT color="green">027</FONT>     * href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng.pdf"&gt;Improved<a name="line.27"></a>
<FONT color="green">028</FONT>     * Long-Period Generators Based on Linear Recurrences Modulo 2&lt;/a&gt; ACM<a name="line.28"></a>
<FONT color="green">029</FONT>     * Transactions on Mathematical Software, 32, 1 (2006). The errata for the paper<a name="line.29"></a>
<FONT color="green">030</FONT>     * are in &lt;a href="http://www.iro.umontreal.ca/~lecuyer/myftp/papers/wellrng-errata.txt"&gt;wellrng-errata.txt&lt;/a&gt;.&lt;/p&gt;<a name="line.30"></a>
<FONT color="green">031</FONT>    <a name="line.31"></a>
<FONT color="green">032</FONT>     * @see &lt;a href="http://www.iro.umontreal.ca/~panneton/WELLRNG.html"&gt;WELL Random number generator&lt;/a&gt;<a name="line.32"></a>
<FONT color="green">033</FONT>     * @version $Id: AbstractWell.java 1416643 2012-12-03 19:37:14Z tn $<a name="line.33"></a>
<FONT color="green">034</FONT>     * @since 2.2<a name="line.34"></a>
<FONT color="green">035</FONT>    <a name="line.35"></a>
<FONT color="green">036</FONT>     */<a name="line.36"></a>
<FONT color="green">037</FONT>    public abstract class AbstractWell extends BitsStreamGenerator implements Serializable {<a name="line.37"></a>
<FONT color="green">038</FONT>    <a name="line.38"></a>
<FONT color="green">039</FONT>        /** Serializable version identifier. */<a name="line.39"></a>
<FONT color="green">040</FONT>        private static final long serialVersionUID = -817701723016583596L;<a name="line.40"></a>
<FONT color="green">041</FONT>    <a name="line.41"></a>
<FONT color="green">042</FONT>        /** Current index in the bytes pool. */<a name="line.42"></a>
<FONT color="green">043</FONT>        protected int index;<a name="line.43"></a>
<FONT color="green">044</FONT>    <a name="line.44"></a>
<FONT color="green">045</FONT>        /** Bytes pool. */<a name="line.45"></a>
<FONT color="green">046</FONT>        protected final int[] v;<a name="line.46"></a>
<FONT color="green">047</FONT>    <a name="line.47"></a>
<FONT color="green">048</FONT>        /** Index indirection table giving for each index its predecessor taking table size into account. */<a name="line.48"></a>
<FONT color="green">049</FONT>        protected final int[] iRm1;<a name="line.49"></a>
<FONT color="green">050</FONT>    <a name="line.50"></a>
<FONT color="green">051</FONT>        /** Index indirection table giving for each index its second predecessor taking table size into account. */<a name="line.51"></a>
<FONT color="green">052</FONT>        protected final int[] iRm2;<a name="line.52"></a>
<FONT color="green">053</FONT>    <a name="line.53"></a>
<FONT color="green">054</FONT>        /** Index indirection table giving for each index the value index + m1 taking table size into account. */<a name="line.54"></a>
<FONT color="green">055</FONT>        protected final int[] i1;<a name="line.55"></a>
<FONT color="green">056</FONT>    <a name="line.56"></a>
<FONT color="green">057</FONT>        /** Index indirection table giving for each index the value index + m2 taking table size into account. */<a name="line.57"></a>
<FONT color="green">058</FONT>        protected final int[] i2;<a name="line.58"></a>
<FONT color="green">059</FONT>    <a name="line.59"></a>
<FONT color="green">060</FONT>        /** Index indirection table giving for each index the value index + m3 taking table size into account. */<a name="line.60"></a>
<FONT color="green">061</FONT>        protected final int[] i3;<a name="line.61"></a>
<FONT color="green">062</FONT>    <a name="line.62"></a>
<FONT color="green">063</FONT>        /** Creates a new random number generator.<a name="line.63"></a>
<FONT color="green">064</FONT>         * &lt;p&gt;The instance is initialized using the current time plus the<a name="line.64"></a>
<FONT color="green">065</FONT>         * system identity hash code of this instance as the seed.&lt;/p&gt;<a name="line.65"></a>
<FONT color="green">066</FONT>         * @param k number of bits in the pool (not necessarily a multiple of 32)<a name="line.66"></a>
<FONT color="green">067</FONT>         * @param m1 first parameter of the algorithm<a name="line.67"></a>
<FONT color="green">068</FONT>         * @param m2 second parameter of the algorithm<a name="line.68"></a>
<FONT color="green">069</FONT>         * @param m3 third parameter of the algorithm<a name="line.69"></a>
<FONT color="green">070</FONT>         */<a name="line.70"></a>
<FONT color="green">071</FONT>        protected AbstractWell(final int k, final int m1, final int m2, final int m3) {<a name="line.71"></a>
<FONT color="green">072</FONT>            this(k, m1, m2, m3, null);<a name="line.72"></a>
<FONT color="green">073</FONT>        }<a name="line.73"></a>
<FONT color="green">074</FONT>    <a name="line.74"></a>
<FONT color="green">075</FONT>        /** Creates a new random number generator using a single int seed.<a name="line.75"></a>
<FONT color="green">076</FONT>         * @param k number of bits in the pool (not necessarily a multiple of 32)<a name="line.76"></a>
<FONT color="green">077</FONT>         * @param m1 first parameter of the algorithm<a name="line.77"></a>
<FONT color="green">078</FONT>         * @param m2 second parameter of the algorithm<a name="line.78"></a>
<FONT color="green">079</FONT>         * @param m3 third parameter of the algorithm<a name="line.79"></a>
<FONT color="green">080</FONT>         * @param seed the initial seed (32 bits integer)<a name="line.80"></a>
<FONT color="green">081</FONT>         */<a name="line.81"></a>
<FONT color="green">082</FONT>        protected AbstractWell(final int k, final int m1, final int m2, final int m3, final int seed) {<a name="line.82"></a>
<FONT color="green">083</FONT>            this(k, m1, m2, m3, new int[] { seed });<a name="line.83"></a>
<FONT color="green">084</FONT>        }<a name="line.84"></a>
<FONT color="green">085</FONT>    <a name="line.85"></a>
<FONT color="green">086</FONT>        /** Creates a new random number generator using an int array seed.<a name="line.86"></a>
<FONT color="green">087</FONT>         * @param k number of bits in the pool (not necessarily a multiple of 32)<a name="line.87"></a>
<FONT color="green">088</FONT>         * @param m1 first parameter of the algorithm<a name="line.88"></a>
<FONT color="green">089</FONT>         * @param m2 second parameter of the algorithm<a name="line.89"></a>
<FONT color="green">090</FONT>         * @param m3 third parameter of the algorithm<a name="line.90"></a>
<FONT color="green">091</FONT>         * @param seed the initial seed (32 bits integers array), if null<a name="line.91"></a>
<FONT color="green">092</FONT>         * the seed of the generator will be related to the current time<a name="line.92"></a>
<FONT color="green">093</FONT>         */<a name="line.93"></a>
<FONT color="green">094</FONT>        protected AbstractWell(final int k, final int m1, final int m2, final int m3, final int[] seed) {<a name="line.94"></a>
<FONT color="green">095</FONT>    <a name="line.95"></a>
<FONT color="green">096</FONT>            // the bits pool contains k bits, k = r w - p where r is the number<a name="line.96"></a>
<FONT color="green">097</FONT>            // of w bits blocks, w is the block size (always 32 in the original paper)<a name="line.97"></a>
<FONT color="green">098</FONT>            // and p is the number of unused bits in the last block<a name="line.98"></a>
<FONT color="green">099</FONT>            final int w = 32;<a name="line.99"></a>
<FONT color="green">100</FONT>            final int r = (k + w - 1) / w;<a name="line.100"></a>
<FONT color="green">101</FONT>            this.v      = new int[r];<a name="line.101"></a>
<FONT color="green">102</FONT>            this.index  = 0;<a name="line.102"></a>
<FONT color="green">103</FONT>    <a name="line.103"></a>
<FONT color="green">104</FONT>            // precompute indirection index tables. These tables are used for optimizing access<a name="line.104"></a>
<FONT color="green">105</FONT>            // they allow saving computations like "(j + r - 2) % r" with costly modulo operations<a name="line.105"></a>
<FONT color="green">106</FONT>            iRm1 = new int[r];<a name="line.106"></a>
<FONT color="green">107</FONT>            iRm2 = new int[r];<a name="line.107"></a>
<FONT color="green">108</FONT>            i1   = new int[r];<a name="line.108"></a>
<FONT color="green">109</FONT>            i2   = new int[r];<a name="line.109"></a>
<FONT color="green">110</FONT>            i3   = new int[r];<a name="line.110"></a>
<FONT color="green">111</FONT>            for (int j = 0; j &lt; r; ++j) {<a name="line.111"></a>
<FONT color="green">112</FONT>                iRm1[j] = (j + r - 1) % r;<a name="line.112"></a>
<FONT color="green">113</FONT>                iRm2[j] = (j + r - 2) % r;<a name="line.113"></a>
<FONT color="green">114</FONT>                i1[j]   = (j + m1)    % r;<a name="line.114"></a>
<FONT color="green">115</FONT>                i2[j]   = (j + m2)    % r;<a name="line.115"></a>
<FONT color="green">116</FONT>                i3[j]   = (j + m3)    % r;<a name="line.116"></a>
<FONT color="green">117</FONT>            }<a name="line.117"></a>
<FONT color="green">118</FONT>    <a name="line.118"></a>
<FONT color="green">119</FONT>            // initialize the pool content<a name="line.119"></a>
<FONT color="green">120</FONT>            setSeed(seed);<a name="line.120"></a>
<FONT color="green">121</FONT>    <a name="line.121"></a>
<FONT color="green">122</FONT>        }<a name="line.122"></a>
<FONT color="green">123</FONT>    <a name="line.123"></a>
<FONT color="green">124</FONT>        /** Creates a new random number generator using a single long seed.<a name="line.124"></a>
<FONT color="green">125</FONT>         * @param k number of bits in the pool (not necessarily a multiple of 32)<a name="line.125"></a>
<FONT color="green">126</FONT>         * @param m1 first parameter of the algorithm<a name="line.126"></a>
<FONT color="green">127</FONT>         * @param m2 second parameter of the algorithm<a name="line.127"></a>
<FONT color="green">128</FONT>         * @param m3 third parameter of the algorithm<a name="line.128"></a>
<FONT color="green">129</FONT>         * @param seed the initial seed (64 bits integer)<a name="line.129"></a>
<FONT color="green">130</FONT>         */<a name="line.130"></a>
<FONT color="green">131</FONT>        protected AbstractWell(final int k, final int m1, final int m2, final int m3, final long seed) {<a name="line.131"></a>
<FONT color="green">132</FONT>            this(k, m1, m2, m3, new int[] { (int) (seed &gt;&gt;&gt; 32), (int) (seed &amp; 0xffffffffl) });<a name="line.132"></a>
<FONT color="green">133</FONT>        }<a name="line.133"></a>
<FONT color="green">134</FONT>    <a name="line.134"></a>
<FONT color="green">135</FONT>        /** Reinitialize the generator as if just built with the given int seed.<a name="line.135"></a>
<FONT color="green">136</FONT>         * &lt;p&gt;The state of the generator is exactly the same as a new<a name="line.136"></a>
<FONT color="green">137</FONT>         * generator built with the same seed.&lt;/p&gt;<a name="line.137"></a>
<FONT color="green">138</FONT>         * @param seed the initial seed (32 bits integer)<a name="line.138"></a>
<FONT color="green">139</FONT>         */<a name="line.139"></a>
<FONT color="green">140</FONT>        @Override<a name="line.140"></a>
<FONT color="green">141</FONT>        public void setSeed(final int seed) {<a name="line.141"></a>
<FONT color="green">142</FONT>            setSeed(new int[] { seed });<a name="line.142"></a>
<FONT color="green">143</FONT>        }<a name="line.143"></a>
<FONT color="green">144</FONT>    <a name="line.144"></a>
<FONT color="green">145</FONT>        /** Reinitialize the generator as if just built with the given int array seed.<a name="line.145"></a>
<FONT color="green">146</FONT>         * &lt;p&gt;The state of the generator is exactly the same as a new<a name="line.146"></a>
<FONT color="green">147</FONT>         * generator built with the same seed.&lt;/p&gt;<a name="line.147"></a>
<FONT color="green">148</FONT>         * @param seed the initial seed (32 bits integers array). If null<a name="line.148"></a>
<FONT color="green">149</FONT>         * the seed of the generator will be the system time plus the system identity<a name="line.149"></a>
<FONT color="green">150</FONT>         * hash code of the instance.<a name="line.150"></a>
<FONT color="green">151</FONT>         */<a name="line.151"></a>
<FONT color="green">152</FONT>        @Override<a name="line.152"></a>
<FONT color="green">153</FONT>        public void setSeed(final int[] seed) {<a name="line.153"></a>
<FONT color="green">154</FONT>            if (seed == null) {<a name="line.154"></a>
<FONT color="green">155</FONT>                setSeed(System.currentTimeMillis() + System.identityHashCode(this));<a name="line.155"></a>
<FONT color="green">156</FONT>                return;<a name="line.156"></a>
<FONT color="green">157</FONT>            }<a name="line.157"></a>
<FONT color="green">158</FONT>    <a name="line.158"></a>
<FONT color="green">159</FONT>            System.arraycopy(seed, 0, v, 0, Math.min(seed.length, v.length));<a name="line.159"></a>
<FONT color="green">160</FONT>    <a name="line.160"></a>
<FONT color="green">161</FONT>            if (seed.length &lt; v.length) {<a name="line.161"></a>
<FONT color="green">162</FONT>                for (int i = seed.length; i &lt; v.length; ++i) {<a name="line.162"></a>
<FONT color="green">163</FONT>                    final long l = v[i - seed.length];<a name="line.163"></a>
<FONT color="green">164</FONT>                    v[i] = (int) ((1812433253l * (l ^ (l &gt;&gt; 30)) + i) &amp; 0xffffffffL);<a name="line.164"></a>
<FONT color="green">165</FONT>                }<a name="line.165"></a>
<FONT color="green">166</FONT>            }<a name="line.166"></a>
<FONT color="green">167</FONT>    <a name="line.167"></a>
<FONT color="green">168</FONT>            index = 0;<a name="line.168"></a>
<FONT color="green">169</FONT>            clear();  // Clear normal deviate cache<a name="line.169"></a>
<FONT color="green">170</FONT>        }<a name="line.170"></a>
<FONT color="green">171</FONT>    <a name="line.171"></a>
<FONT color="green">172</FONT>        /** Reinitialize the generator as if just built with the given long seed.<a name="line.172"></a>
<FONT color="green">173</FONT>         * &lt;p&gt;The state of the generator is exactly the same as a new<a name="line.173"></a>
<FONT color="green">174</FONT>         * generator built with the same seed.&lt;/p&gt;<a name="line.174"></a>
<FONT color="green">175</FONT>         * @param seed the initial seed (64 bits integer)<a name="line.175"></a>
<FONT color="green">176</FONT>         */<a name="line.176"></a>
<FONT color="green">177</FONT>        @Override<a name="line.177"></a>
<FONT color="green">178</FONT>        public void setSeed(final long seed) {<a name="line.178"></a>
<FONT color="green">179</FONT>            setSeed(new int[] { (int) (seed &gt;&gt;&gt; 32), (int) (seed &amp; 0xffffffffl) });<a name="line.179"></a>
<FONT color="green">180</FONT>        }<a name="line.180"></a>
<FONT color="green">181</FONT>    <a name="line.181"></a>
<FONT color="green">182</FONT>        /** {@inheritDoc} */<a name="line.182"></a>
<FONT color="green">183</FONT>        @Override<a name="line.183"></a>
<FONT color="green">184</FONT>        protected abstract int next(final int bits);<a name="line.184"></a>
<FONT color="green">185</FONT>    <a name="line.185"></a>
<FONT color="green">186</FONT>    }<a name="line.186"></a>




























































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